Cirriphyllum piliferum (Hedw.) Grout
Hair-pointed Feather Moss
Basis for Listing
Cirriphyllum piliferum (hair-pointed feather moss) has a nearly continuous northern-hemishphere distribution of temperate affinity. It has been recorded regionally from Ontario, Wisconsin, and the Upper Peninsula of Michigan (Ignatov 2008; Janssens 2010). In Minnesota, only two populations of C. piliferum have been found (Fillmore and Washington counties). Despite extensive surveys of suitable habitat of algific slopes on the Paleozoic Plateau and of spring fens throughout the state, no additional populations have been encountered. Because so few populations have been documented in Minnesota, there is too little information available to detect a statewide population trend at this time. Climate change, and the resulting disappearance of these specialized mesohabitats, will stress survival of the existing populations in the state. Based on the species’ extreme rarity and perceived threats to its habitat, Cirriphyllum piliferum was designated threatened in 2013.
Both from its field aspect and from a cursory close-up look, C. piliferum appears very similar to several other Brachytheciaceae. This large and unwieldy family has recently been extensively revised (Ignatov and Huttunen 2002; Ignatov 2008). Cirriphyllum piliferum is now recognized as the only North American species belonging to the genus in which it was classified by Grout in 1898 (Crum and Anderson 1981; Ignatov 2008). The species forms shiny whitish-green mats, with a somewhat pinnate branching (though both Minnesota vouchers consist of only a few stems). On closer inspection, C. piliferum is differentiated from other Minnesota Brachytheciaceae by its long-filiform apiculate apex (easily seen with back-lighting and a 20x hand lens, particularly when the plants are dry), in addition to the distinctly terete branches and the gradually inflated but fairly sharply delimited alar cells in groups reaching half-way to the costa. Under the microscope, the longly decurrent leaves, narrowly linear medial leaf cells, and serrate margins are reminiscent to those of Steerecleus (Rhynchostegium) serrulatum (steerecleus moss). However, there is no confusion possible between these species when the apex is studied: those of S. serrulatum are far more gradually acuminate and curiously twisted. The branches of S. serrulatum are also somewhat complanate rather than distinctly terete as in C. piliferum because of the latter’s strongly imbricate leaves.
Cirriphyllum piliferum grows on soil and decayed wood in moist and shady places within mesohabitats such as algific slopes and spring fens; in Minnesota it occurs on southern open talus (The Blufflands Subsection of the Paleozoic Plateau) and in southern rich conifer swamp (St. Paul-Baldwin Plains and Moraines Subsection of the Minnesota and NE Iowa Moraines). Commonly associated bryophyte species within these mesohabitats are Thuidium delicatulum (delicate thuidium moss), Climacium dendroides (tree climacium moss), Plagiomnium ellipticum (elliptic plagiomnium moss) and P. cuspidatum (toothed plagiomnium moss), Brachythecium salebrosum (brachythecium moss), and Conocephalum salebrosum (snakeskin liverwort).
Biology / Life History
In Minnesota, this species has been found as a few scattered plants within patches of other more aggressive species (Climacium, Brachythecium, Eurhynchium [Oxyrrhynchium], Rhytidiadelphus, and Thuidium species). Thus it is assumed to be a non-aggressive perennial moss, at least in this state.
Conservation / Management
Climate change may threaten the species' viability in Minnesota. The degradation of the algific-slope or maderate-cliff conditions or the disruption of spring-fen discharge would likely eliminate the species.
Best Time to Search
The best time to search for C. piliferum is from May through September or essentially anytime the ground is not covered by snow.